1. Field of the Invention
The present invention relates to a communication system, and in particular, to a communication system including a local terminal apparatus connected with a local network, a remote terminal apparatus connected with an external network, and a control apparatus interposed between the local network and the external network.
2. Description of the Related Art
FIG. 32A is a schematic block diagram showing a configuration of a conventional communication system, FIG. 32B is a schematic diagram showing a signal flow in the conventional communication system shown in FIG. 32A, and FIG. 33 is a schematic block diagram showing a functional configuration of a control apparatus PC shown in FIG. 32A.
A conventional communication system shown in FIG. 32A is constituted by comprising the followings:
(a) a local terminal apparatus PA connected with a predetermined local network LN1;
(b) a remote terminal apparatus PB connected with an external network EN1 such as the Internet of an open network or the like, and
(c) the control apparatus PC connected with both of the local network LN1 and the external network EN1.
The control apparatus PC is provided with a data storage memory M.
Each of the local terminal apparatuses PA is, for example, a fire alarm sensor for disaster prevention including functions of a thermo-detector, a smoke detector and flame detector, and a group of lighting equipments. An acquired status value information of a group of the local terminal apparatuses PA (this information includes, in particular, information having no highest priority emergency such as a temperature value, a status of turning on or off of each lighting equipment) is fetched into the control apparatus PC in accordance with a return request command which is transmitted from the control apparatus PC to a group of the local terminal apparatuses PA, namely, each apparatus of the group of the local terminal apparatuses PA returns an answer signal to the control apparatus PC via the local network LN1, in response to a request signal for status monitor which is transmitted from the control apparatus PC to each local terminal apparatus PA.
The operation of the control apparatus PC will be further described below with reference to FIG. 33. In the control apparatus PC, when status value information is fetched into an interface PC1 connected with the local network LN1, a packet analyzer section PC2 analyzes a signal including the status value information according to a predetermined protocol of the local network LN1 so as to read the status value information. Thereafter, a data updating section PC3 writes the status value information into the data storage memory M as new data. Namely, the control apparatus PC stores the fetched status value information into the data storage memory M. The storing operation is substantially periodically carried out although it depends upon a degree of traffic congestion in communication between the control apparatus PC and each local terminal apparatus PA, and then, the status value information stored in the data storage memory M is updated every communication therebetween. In this case, the data storage memory M is provided for storing data of the status value information in preparation for a request signal from the remote terminal apparatus PB, and is not an apparatus functioning as a buffer memory for decoding a signal received by the control apparatus PC.
In the case of reading the status value information of each of local terminal apparatuses PA, the remote terminal apparatus PB makes an access to the control apparatus PC via the external network EN1, and then, reads out the status value information of each of the local terminal apparatuses PA from the data storage memory M of the control apparatus PC.
Referring now to FIG. 33, in the control apparatus PC, a packet analyzer section PC5 analyzes an external data received by the interface PC 4 connected with the external network EN1. Then, if the external data is a request signal for status value information from the remote terminal apparatus PB, a data reading section PC6 reads the status value information stored in the data storage memory M. Then, a packet generator section PC7 converts the status value information into an answer signal in a form of a data format capable of transmitting to the remote terminal apparatus PB, and thereafter, the packet generator section PC7 returns the answer signal to the remote terminal apparatus PB via an interface PC4.
FIG. 34 is a schematic block diagram showing a configuration of another conventional communication system, and FIG. 34 shows a system for apartment house or multiple dwelling houses and its peripheral unit arrangement.
Referring to FIG. 34, the apartment house system S1 is constituted by comprising an entryphone S11 provided in each dwelling unit, a door phone S12 mainly provided at the entrance of each dwelling unit, a facility input terminal S13, a lobby entryphone S14, and an alarm supervisory apparatus S15. More specifically, the equipment input terminal S13 is used for inputting setting information of the water supply and drainage facility and for inputting setting information for lighting equipment management and going in-and-out management of a common area facility such as a lobby or the like. The lobby entryphone S14 is provided in a common area such as a lobby, and is used for temporarily answering to a visitor and giving a permission of going in and out of the building. The alarm supervisory apparatus S15 is connected with the entryphone S11, the equipment input terminal S13 and the lobby entryphone S14, and is used as a host machine in the apartment house system S1. Further, the alarm supervisory apparatus S15 is connected with a service center of security company so as to make a contact with there using a dedicated telephone line TEL1 via a communication apparatus S16.
Moreover, in addition to the above apartment house system S1, a service system S2 connected with an electric power company, a gas company and the Waterworks Bureau is also employed. A supervisory input apparatus S21 makes a check for a quantity of used electricity, gas and water of each dwelling unit so as to supervise a used quantity of them, and then, periodically informs a quantity of used source of each dwelling unit to the power company, a gas company and the Waterworks Bureau at the end of month, respectively. By this arrangement, the power company, the gas company and the Waterworks Bureau have no need of carrying out meter reading for each dwelling unit, and merely send an account to each dwelling unit. Therefore, there is no need of sending a meter reading person, so that a labor cost can be reduced.
Further, in the example shown in FIG. 34, a home delivery service system S3 is employed together with the apartment house system S1 and the service system S2 connected with then electric power company, the gas company and the Waterworks Bureau. For example, in an apartment house, a home delivery service box S31 is used as a home mailbox previously allocated to each dwelling unit. The delivery service box S31 is provided with sensors such as a weighting sensor, an infrared sensor and a tilt angle sensor, capable of identifying the presence of baggage. Further, the delivery service box S31 has a sensing function for obtaining such confirmation as whether or not a delivered good is taken out and its takeout time and the like after the delivered good is put into the home delivery service box S31 by a delivery service provider. The status information acquired by these sensors is readable from a management company such as a home delivery service box manufacturer using a dedicated telephone line TEL3.
However, in the conventional communication system shown in FIGS. 32A, 32B and 33, the status value information acquired by the local terminal apparatuses PA is stored in the data storage memory M, and further, the status value information returned in accordance with a request signal from the remote terminal apparatus PB is information which has been already stored in the data storage memory M. For this reason, the status value information is lack of freshness, that is, reliability of being real time information. Therefore, the above conventional communication system is unsuitable in the case of obtaining the latest status value information as much as possible.
Moreover, the control apparatus PC must be necessarily provided with the data storage memory M. In addition, the construction is employed such that the status value information is stored in the data storage memory M. For this reason, when the number of local terminal apparatuses PA and a quantity of data increase, the data storage memory M needs to have a large capacity, and this leads to such a problem that the data storage memory M must be made so as to have a large scale.
On the other hand, in another conventional communication system shown in FIG. 34, the dedicated contracted telephone lines TEL1, TEL2 and TEL3 are independently used with respect to the apartment house system S1, the service system S2 connected with the electric power company, the gas company and the Waterworks Bureau and the home delivery service system S3, respectively. For this reason, the telephone line is required with respect to each of these systems S1 to S3, and this leads to high communication cost.
In the apartment house system S1, although an emergency message is given to a predetermined contracted place such as a security company service center, the contracted company can not perform supervision and setup for control information from the outside of the apartment house system S1 in the light of privacy protection.